Preparing theromoplastics for dyeing

ABSTRACT

THE DYE RECEPTIVITY AND ANTISTATIC OF POLYMERIC MATERIALS, E.G. SYNTHETIC HYDROPHOBIC POLYMERS, E.G. POLYETHYLENE TEREPHTHALATE, ARE IMPROVED BY ABSORBING INTO POLYMERS (PRIOR TO DYEING) A BICYCLIC AMIDOACETAL, AND SUBJECTING SAID AMIDOACETAL TO RING CLEAVAGE, SAID RING CLEAVAGE BEING EFFECTED AT 20-100*C. BY CONTACT WITH A LIQUID WHICH HAS AS AN ESSENTIAL INGREDIENT THEREOF A MEMBER SELECTED FROM THE GROUP CONSISTING OF (A) WATER, (B) A CARBOXLIC ACID HAVING FROM 1-18 CARBON ATOMS; AND (C) AN ANHYDRIDE OF (B), THE RESULTANT CLEAVED MOLECULES BEING DYEABLE AND DIFFICULT TO REMOVE FROM THE POLYMER.

"United States Patent 01 lice 3,50,2l4 Patented Aug. 17, 1971 PREPARING THERMOPLASTICS FOR DYEING Roland Feinauer, Haltern, and Wolfgang Seeliger, Johann Schlimme van Brunswijk, and Hans Busch, Marl, Germany, assignors to Chemische Werke Huels Aktiengesellschaft, Marl, Germany No Drawing. Filed Aug. 26, 1968, Ser. No. 755,428

Claims priority, applicatigg 2geirmany, Sept. 15, 1967,

Int. 01.35411 N48 US. Cl. 117-62.1 19 Claims ABSTRACT OF THE DISCLOSURE BACKGROUND OF THE INVENTION This invention relates to improving the dyeability of polymeric materials.

Fibers and films of thermoplastic synthetic materials, such as linear polyesters, polyamides and polyolefins, exhibit, as contrasted to their good mechanical properties, several serious disadvantages compared to natural fibers, such as wool or cotton, especially when employed as textile materials. These disadvantages, which are particularly pronounced in the textile sector, stem from the hydrophobic properties of the synthetic materials. Thus, fibers of linear polyesters or polyolefins cannot be dyed satisfactorily by means of conventional dyeing processes for dyeing cotton, wool, natural silk or regenerated cellulose. Furthermore, fibers and films of synthetic materials are electrically charged by static electricity during processing or in use, under the influence of friction. This charging by static electricity interferes considerably with the processing or use of such fibers or films.

Numerous methods have been devised to overcome these disadvantages inherent in articles of synthetic materials; however, none of these methods is completely satisfactory from all standpoints.

In order to dye polyester fibers, two processes predominate in the technical field; where these processes can be employed, they yield satisfactory results from the viewpoint of dyeing technology, but they still present other substantial disadvantages (see, for example, P. Linsemann, Textilpraxis [Textile Practice], 20 (1965) 7, 579).

In one of these processes the dyeing is conducted with disperse dyes at temperatures ranging considerably above 100 C. This entails a large technical expenditure, inasmuch as the dyeing must be conducted under pressure in a sealed apparatus, and is, therefore, restricted inter alia by equipment availability.

In the second technical process, polyesters are dyed with disperse dyes at the boiling temperature with the addition of carriers. This procedure also is unsatisfactory. The need for carriers, often very diflicult and costly to obtain, makes this dyeing process very expensive. The carriers, moreover, possess still other disadvantages. They are in most cases strongly odorous and poisonous chlorinated aromatics or phenolic compounds. Thus, when operating with these substances, additional safety measures are required to protect the dyeing personnel, but there is always the danger of accidents due to unexpected circumstances.

There are other numerous processes for dyeing polyester fibers and fibers of polyolefins in deep shades without carriers or without the use of pressure. Thus, many patents describe processes for improving the dyeability by chemical modification of poly-(ethylene glycol terephthalate) by employing a small amount of a second dicarboxylic acid or a second diol as a comonomer. The better color absorption obtained without a carrier by such a process, is achieved, however, at the price of lowering the quality of the polymer, since the chemical modification markedly lowers the melting range of the fibers and reduces the crystallinity thereof (see, in this connection, for example, H. Berg, Chemiefasern [Chemical Fibers], 1965, Vol. 9, page 654). As a result the fibers have lower temperature stability (ironing fastness) and lower strength. Graft and block copolymers of poly-(ethylene glycol terephthalate) likewise exhibit, together with improved dyeing properties, considerable disadvantages heretofore preventing wide-range use of such copolymers. In addition to their greatly decreased ability to crystallize the hydrolytic stability of these polymers is strongly reduced (H. Mark, Chemiefasern, 1966, Vol. 4, p. 261).

Experiments for improving the dyeability of polypropylene by mixing therewith polyvinyl acetate, polyacrylates, polyvinyl ethers (German published application 1,195; 901) or polyvinyl pyridine (US. Pat. 3,315,014) have likewise proved unsatisfactory since the polypropylene properties are altered too much by the admixed components.

In order to avoid impairment of the properties of the fiber material by chemical modification, attempts have been made to obtain improved dyeability by post-treating synthetic fibers with suitable substances, e.g. polyester treated with various compounds, especially amino alcohols (French Pat. 1,104,375 and US. Pat. 2,647,104).

The improvement in the dyeability of the thus-formed articles of high-molecular polyesters obtained thereby, however, is not sufficient to permit dyeing without carriers or without employing dyeing temperatures above C.

In German published application 1,201,549, a process is disclosed for improving dye affinity by treating molded linear polyesters with complexes of boron trifluoride and organic compounds. However, the technical significance of this process is attenuated by the need for expensive safety precautions in handling of the poisonous boron trifluoride.

Processes for the surface treatment of polyester filaments with polyglycols have likewise been described. In the process of DAS [German published application] 1,2,33,5 33, this finishing procedure must be conducted during fiber manufacture, namely before stretching. Finishing the completed extended and heat-set fiber or even the strands of yarn or the fabrics in thus impossible in accordance with this process. However, a finishing procedure effected subsequent to the shaping of the polymer (see, for example, Ullmann, Enzyklopadie der technischen Chemie [Encyclopedia of Technical Chemistry, vol. 17/ 1966, p. 259, under D) is of technical advantage because for many purposes (e.g. continuous filaments for tire cord, staple fiber for upholstery material) wherein undyed fiber is employed and a finishing procedure for improving the dyeability is unnecessary. Thus, the process of DAS 1,233,533 is impractical since it necessitates a complicated rearrangement of the continuously conducted fiber manufacturing process and would be relatively inflexible to the demand for undyed products.

Furthermore, since polyester fibers, for example, absorb different dyestuffs to different degrees, different amounts of carrier must be used during carrier dyeing to regulate the absorption, but in the process of DAS 1,233,- 533, wherein the finishing process is conducted during the continuous fiber manufacturing procedure, no consideration can be given to such differences in dye affinity. This is a particular problem for the one-bath dyeing of fabric blends, for example, polyester-Wool, since for such fabrics the boiling period must be controlled within a narrow range. As a result, fabric blends based on polyester material finished in accordance with the process of DAS 1,233,533 are colored to different strengths, depending on the dyestuff employed, there being no possibility to make the necessary adjustment.

Other processes for the treatment of molded articles of linear polyesters at high temperature 200 C.) with glycerin (DAS 1,229,032) or with monoor dicarboxylic acids, esters of higher-molecular alcohols, or phenols, (DAS 1,148,520) are difiicult to conduct technically, since polyesters very readily degrade in viscosity at high temperatures, and thus the properties are altered in an undesirable manner.

It is also to be noted in most processes for the antistatic finishing of molded articles from thermoplastic synthetic matrials, that antistatic agents are applied from an aqueous dye liquor, but these agents are not laundryfast and are removed from the material after a few washing steps. Said processes include finishing with polyalkylene glycols or derivatives thereof (e.g., US. Pat. 3,161,594).

In other special processes specific for producing more or less laundry-fast anti-static materials, the results are unsatisfactory for other reasons. In these processes, a water-insoluble, antistatically effective film is generally produced on the surface of the molded article. However, this surface film causes such disadvantageous properties as an altered feel, and this new surface, in turn, can lead to considerable difficulties in further processing steps. Illustrative processes of this type are described in German published applications 1,211,577; 1,194,363; and 1,209,542.

Finally, in accordance with DAS 1,228,056, molded articles with antistatic properties can be produced from thermoplastic materials by mixing therewith certain oxyalkylamines; however, this procedure cannot be employed at all for high-melting polyesters, such as poly-[1,4-bishydroXymethyl-cyclohexane terephthalate] SUMMARY OF THE INVENTION By immersing undyed films, fibers, yarns or webs, etc. of synthetic hydrophobic thermoplastic polymer for a period of time in a bicyclic amidoacetal, the dyestuff affinity and antistatic properties of the subsequently dyed polymer is improved. The bicyclic amidoacetal is of the formula:

o R4 n O wherein R is either hydrogen; an aliphatic residue of from 1-17 carbon atoms, such as alkyl, e.g. methyl, nonyl and cetyl or an aromatic residue, wtih 6 carbon atoms, e.g. phenyl,

each of R R and R is, independently, either hydrogen, aliphatic, preferably alkyl of 1-4 carbon atoms, e.g. methyl and butyl, or aryl with 6 carbon atoms, e.g. phenyl, and R may also be alkoxymethylene, e.g. methoxymethylene and lauryloxymethylene, the alkoxy group having from 1 to 12 carbon atoms; lower alkenyloxymethylene, e.g. allyloxymethylene; or phenoxymethylene and n is 2 or 3.

It is thus an object of the subject invention to increase the dyeability of synthetic thermoplastics.

It is a further object to increase said dyeability without the use of a carrier and without modifying the nature of the thermoplastic with another polymer or comonomer.

Another object is to improve the antistatic properties of synthetic thermoplastics.

A still further object is to devise a treatment which can be effected at any time from the manufacture up to the dyeing of the thermoplastic polymer.

It is also an object of the invention to provide a process wherein the nature and degree of treatment can be varied for different polymers and for different sections of the same polymer.

The overall objective of this invention is thus to obtain a good dyeability without the use of carriers, and, simultaneously, satisfactory antistatic properties by treating shaped bodies, such as fibers and films of, preferably, high-melting synthetic thermoplastic, particularly linear polyesters of the type of poly-(ethylene glycol terephthalate) and of poly-[1,4-bis-(hydroxymethyl)-cyclohexane terephthalate].

DEAILED DISCUSSION OF THE INVENTION The preceding objectives are obtained by treating a shaped body of synthetic thermoplastic polymer with at least one bicyclic amidoacetal which is either a 4,6-dioxa- 1-azabicyclo[3,3,0]octane or a 5,7-dioxa-l-azabicyclo [4,3,0]nonane. In addition to the unsubstituted compounds, the preferred amidoacetals which are octanes can be substituted in the 5-position with an aliphatic group having from 1 to 17 carbon atoms, inclusive, e.g. methyl, octyl, dodecyl and cetyl, or with an aryl group, preferably phenyl; and in each of the 3- and 7-positions, independently, with lower alkyl, e.g. methyl and butyl, an aryl group, preferably phenyl.

The 2- and 3-positions can be independently substituted with any two of the indicated substituents, it being preferred that the 2-position is a methylene group, Whereas the 7-position is generally only monosubstituted, with any of the indicated substituents and also with alkoxymethyl, the alkoxy having from 1-12 carbon atoms, e.g. methoxymethyl and lauryloxymethyl, lower alkenyloxymethyl, preferably saturated in the a-position, e.g. allylox ymethyl, or with aryloxymethyl, preferably phenoxymethyl.

The preferred amidoacetals which are nonanes can be similarly substituted in the corresponding positions. Thus, the 6-position of the nonanes can bear the same substituents as the 5-position of the octanes; the 2-, 3-, and 4-positions of the nonanes can bear the same substituents and in the same manner as the 2- and the 3-positions, respectively, of the octanes, it being preferred that the 2- and 3-positions be methylene groups. The 8 position of the nonanes corresponds to the 7 position of the octanes.

The treatment may be effected by merely immersing the shaped thermoplastic body into amidoacetal. In this manner, the amidoacetal is absorbed into the thermoplastic.

It a bicyclic amidoacetal which is solid or viscous at the treatment temperature is employed, the treatment is advantageously carried out so that the shaped bodies of synthetic thermoplastic is treated with a solution of the bicyclic amidoacetal in an inert solvent, such as,

for example, a lower alkanol, e.g. isopropanol, alcohol, or an aromatic hydrocarbon, e.g. toluene. After this treatment, any excess superficially adhering amidoacetal is suitably removed, for instance, by stripping or squeezing. The period of immersion can be varied over a considerable range, finite favorable results being obtained by contacting the polymer for a sufficient time to effect finite absorption, e.g. from several minutes to 1 hour. The extent of absorption is also dependent upon the particular thermoplastic and the temperature of the arnidoacetal. Said temperature is ordinarily from 200 C., and preferably from 50150 C. The bicyclic amidoacetals penetrate deeply into the thermoplastic, due to the special structure of the former.

Following said immersion, the thus-treated shaped body is placed in intimate contact with a fluid. This treatment can also be effected by mere immersion. The fluid is either water, a carboxylic acid having from 118 carbon atoms or an anhydride thereof.

When the carboxylic acid or the carboxylic acid anhydride is not sufiiciently fluid, it is dissolved in a suitable solvent, such as a lower alkanol, e.g. ethanol. The concentration of the carboxylic acid or anhydride in the solvent can be varied over virtually the entire range possible. Although the properties may not be affected to the same degree with a substantial change in concentration, the dyeability and antistatic properties of the shaped body will be improved. This fluid contact is preferably effected over a period of several minutes to 1 hour and at a temperature from 20 C. to 100 C., and results in a chemical reaction with the bicyclic amidoacetal present in the fiber, with ring opening of the amidoacetal; bulky molecules (with hydrophilic groups) which can be removed from the fibers only with CHR HOR 1 R4 ,1 COR1 in which R may be hydrogen or an acyl residue of said carboxylic acids.

Due to this treatment, the shaped articles of thermoplastic synthetic polymers receive excellent properties, such as good dyeability with disperse dye, even Without the use of carriers, and good antistatic properties. The concurrence of both technically important properties is particularly surprising.

Suitable carboxylic acids include alkanoic acids, such as formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, caprylic acid, pelargonic acid, lauric acid, stearic acid and oleic acid; monocyclic aromatic acids, such as benzoic acid; diand polybasic acids, such as phthalic acid or trimellitic acid. Especially preferred an'nyilrides are acetic acid anhydride and phthalic acid anhydride. If the molded bodies, after treatment with the amidoacetal, are post-treated with Water, they can subsequently be dried; when post-treated with carboxylic acids or the anhydrides thereof, it is advantageous to post-treat the bodies for 'some time, before drying, with water, preferably at the boiling temperature, in order to remove any water-soluble compounds adhering on the surface of the bodies. However, it is also possible to omit post-treatment of the materials treated with bicyclic amidoacetals, since they will come into contact with water or steam in the course of further processing, for example, during dyeing or when allowed to stand in air. Of course, it is also possible to provide the shaped materials, in addition to the treatment with bicyclic amidoacetals, with still other antistatically effective agents.

The expression shaped articles or shaped bodies includes fibers, yarns, and webs and fabrics made therefrom, as well as belting, sheets, films, molded objects, etc. These shaped articles can be produced from synthetic thermoplastics such as polyolefins, e.g. polyethylene and polypropylene; polyvinyl compounds, e.g. polystyrene, polyvinyl chloride; polyacrylates, such as polymethacrylates; polycondensates, such as linear polyesters of the type of poly(ethylene glycol terephthalate) and of poly- 1,4-bis (hydroxymethyl)-cyclohexane terephthalate] and polyamides, such as polyamide 6, polyamide 6-6, polyamide 11 and polyamide 12. Fibers and films from (a) saturated polyesters, such as poly-(ethylene glycol terephthalate) and poly- 1,4-bis(hydroxymethyl -cyclohexane terephthalate], from (b) polypropylene and from (c) polyamides are preferably used for the process of the invention.

The bicyclic amidoacetals (not the subject of the instant invention), suitable for the process of this invention, can be produced in a simple manner from epoxides and cyclic iminoesters according to the disclosure of German Patent application C 38,818 IVd/ 12p, which corresponds to French Pat. No. 1,518,386.

Preferred amidoacetals for the process of this invention are the following compounds: S-methyl 4,6 dioxa-lazabicyclo[3,3,0]octane and 3,5-dimethyl 4,6 dioxa-lazabicyclo[3,3,0] octane. Further illustrative amidoacetals useful for said process include, but are not limited to:

5 -methy1-3-phenyl-4,6-dioxal-azabicyclo [3,3 ,0] octane, 5-methyl-3 -phenoxymethyl-4,6-dioxal-azabicyclo- [3 ,3,0] octane, S-ethyl-3-phenyl-4,6-dioxa-l-azabicyclo [3 ,3,0 octane, 5-ethyl-3-allyloxymethyl-4,6-dioxa-1-azabicyclo- [3 ,3,0] octane,

3 ,5 -diphenyl-4,6-dioxa- 1-azabicyclo[3 3 ,0] octane, 3aphenoxy-methyl-5-phenyl-4,6-dioxal-azabicyclo- [3 ,3,0] octane,

3 -phenoxymethyl-5-propyl-4,6-dioxa- 1 -azabicyclo- [3 ,3,0] octane, 5-ethyl-3-lauryloxyrnethyl-4,6-dioxal-azabicyclo- [3,3,0] octane, 5-phenyl-4,6-dioxal-azabicyclo 3,3,0] octane, 4-ethyl-6-phenyl-8-phenoxymethyl-5,7-dioxa-1- azabicyclo [4,3 ,0] nonane, 4,4-dimethyl-6-phenyl-8-phenoxymethyl-5,7-dioxa-1- azabicyclo [4,3 ,0] nonane,

6-methyl-8-phenyl-5,7-dioxal-azabicyclo [4,3 ,0] nonane,

and

4-phenyl-6-undecyl-8 -allyl-oxymethyl-5,7-dioxa-1- azabicyclo [4,3 ,0] nonane,

2,3 ,5 ,7-tetramethyl-4,6-dioxa- 1 -aza-bicyclo [3 ,3 ,0] octane,

2-methyl-5-ethyl-4,6-dioxa- 1-aZa-bicyclo[ 3 ,3 ,0 octane,

and

2,3-dimethyl-4-ethyl-6-phenyl-8-phenoxy-methyl-S ,7-

dioxa-1-aza-bicyclo[4,3 ,0] nonane.

Particularly advantageous effects are obtained by treating the shaped bodies with amidoacetals under conditions which lead to a nitrogen absorption of 0.0011% based on the weight of the polymer. In this connection, the nitrogen absorption is regulated by the duration and temperature of the treatment and by the addition of solvents.

The advantageous properties, such as good dyeability during dyeing without the use of carriers and/or good antistatic behavior of the molded bodies of thermoplastic synthetics attained by the finishing process of this invention are reflected in the following examples.

Without further elaboration, it is believed that one skilled in the art can, using the preceding description utilize the present invention to its fullest extent. a The following preferred specific embodiments are, therefore, to be construed as merely illustrative, and not limitative of the remainder of the specification and claims in any way whatsoever.

EXAMPLES 1-5 In each of Examples 1-5 listed in the table below, 1 gram of staple fiber of poly-[1,4-bis-(hydroxymethyl)- cyclohexane terephthalate] (3.0 den./ 64 mm., glossy) is immersed for 1530 minutes at the temperature stated in the table in 3,5-dimethyl-4,6-dioxa-l-azabicyclo[3,3,0]-

octane, hereafter DMO. Thereafter, thus treated fiber is submerged in cold water for 30 minutes. In Examples 4 and the thus treated fiber is boiled for 30 minutes in water. Following this treatment, the fiber is once again washed well, and dried for 2 hours at 110 C. in a drying chamber, 24 hours at 50 C. in a vacuum drying chamber and thereafter in a vacuum desiccator until constant weight is attained. This procedure is followed in order to demonstrate the effect of the process of this invention independently of any residual moisture. The nitrogen content of the samples yields information regarding the degree of absorption by the synthetic.

Depth of Treatment color, temp. with N-contcnt polyester Palanil" DMO 1 by Weight red B, blue R Example C (percent) Eastman (BASIN 3,5-dimethyl-4,6-dioxa-1-azabicyc1o[3,3,0]octane. 2 The depth of color is judged according to the following scale: 0=no coloration; 1=slight coloration; 2=good coloration; 3=vory good coloratlon.

3 Badische Anilinund Soda-Fabrik.

Different specimens of each of the samples of Examples 1-5 are separately dyed with each of the disperse dye listed in the above table, without the addition of a carrier, in accordance with the following recipe:

Preliminary purification:

minutes at 80 C. with water+2 ml./l. of formic acid. Rinse with cold Water.

Dye bath and dyeing:

0.5 g. of staple fiber 0.2 g. of ammonium sulfate 1 g. of wetting agent (ammonium-alkylbenzene sulfonate) 5 g. of Glauber salt 0.05 g. of disperse dye 100 ml. of water Boil for 2 hours under reflux. Rinse with hot and cold water.

Post purification:

30 minutes at 60 C. with water+l g./l. of ammonium-alkylbenzene sulfonate+1 ml./l. of acetic acid. Rinse with warm and cold water.

EXAMPLE 6 A strand of yarn of 100% poly-[1,4-bis-(hydroxymethyl)-cyclohexane terephthalate] is immersed for 30 minutes in DMO at 100 C. and thereafter for 30 minutes in cold water. After drying, a nitrogen content of 0.63% is found for the yarn. The thus-finished yarn is tested with respect to anti-electrostatic properties. After being rubbed with a V4A metal rod, no measurable charging is observed (measured with the static voltmeter of the Roths child company). In contrast thereto, a finished but untreated sample of the same yarn exhibits considerable electrical charging volts). The pretreated yarn is dyed with Resolin blue RRL (Bayer) without the use of a carrier. The obtained color depth is practically as good as in a yarn which was not pretreated but dyed with Levegal PT as the carrier (grade 3, see Example 1),

whereas the dyeing of an untreated yarn without any carrier leads only to a very light color shade (grade 1).

EXAMPLES 7-10 Percent by weight Color depth,

DMO content Palanil blue Example solution N content R (BASF) EXAMPLE 11 Two grams of staple fiber of poly-[1,4-bis-(hydroxymethyl)-cyclohexane terephthalate] is immersed in DMO for 30 minutes at 100 C. Thereafter, the sample is dipped into glacial acetic acid for 30 minutes at room temperature, and then boiled with water for 30 minutes. Subsequently, the sample is once again thoroughly washed and dried as set forth in Example 1.

EXAMPLES 12-15 Examples 12-15, listed in the table below, are conducted in the same manner as Example 11, the substances X set out in the table being employed in place of glacial acetic acid.

Color depth, 1

N-Content, polyester percent red B,

Example Substance X employed by weight Eastman 11 Glacial acetic acid 0. 14 2 12 Acetic acid anhydride 0. 24 2 13- 50% lauric acid ethanol 0. 12 3 14 20% lauric acid ethanol 0.073 8 l5- 10% lauric acid ethanol 0. 060 3 1 Gradingsce Example 1.

It can be seen from the table that the treated fiber samples can be dyed without a carrier with polyester red B (Eastman) to a good to very good degree (grading-see Example 1).

EXAMPLE 16 Two grams of staple fiber of poly-(ethylene glycol terephthalate) (3 den./ 75 mm., matte) is dipped into DMO for 30 minutes at 100 C. Thereafter, the sample is treated for 30 minutes with cold water and for another 30 minutes with boiling water.

The thus treated fiber sample is dyed with polyester red B (Eastman) without carrier in deep shades (grades 2 to 3).

EXAMPLE 17 Two grams of polypropylene endless fiber is treated with DMO for 30 minutes at C. Subsequently, the sample is treated with cold water for 30 minutes, washed well with water, and dried in a vacuum drying chamber at 50 C. and in a vacuum desiccator until constant weight is attained.

The analysis yields a nitrogen content of 0.33%.

The thus-treated fiber sample can be dyed in light shades with polyester red B (Eastman) after boiling for 30 minutes (grade 1), whereas an untreated comparison sample, under the same dyeing conditions, does not show any color absorption whatsoever (grade 0).

9 EXAMPLES 1s-20 In Examples 1820 listed in the table below, films of polypropylene (Vestolen P, Example 18) polyamide.-12 (Vestamid, Example 19) and poly-(ethylene glycol terephthalate) (Example 20) are dipped into DMO for 30 minutes at 100 C. Subsequently, the samples are treated for 30 minutes with cold water and dried until a constant weight is obtained. In a further series of tests, after the treatment with DMO, the samples are treated for 30 minutes with boiling water rather than with cold water. In the table, the nitrogen content values of the untreated films (blank value) and the films treated in accordance with the above are set forth. The nitrogen data clearly indicate an absorption of the DMO by the films. For testing with respect to antistatic properties, the films, after being briefly rubbed with a cotton cloth, areheld about 1 cm. above cigaret ashes. The blank samples strongly attract the ashes, due to electrical charging sign), whereas the films treated with DMO and cold water do What is claimed is:

1. A process comprising absorbing into a polymer a bicyclic amidoacetal; and subjecting said absorbed amidoacetal to ring cleavage in situ to form bulky absorbed molecules, whereby said bulky molecules are diflicult to remove from the synthetic thermoplastic polymer, said ring cleavage being effected by contact with a liquid which has as an essential ingredient thereof a member selected from the group consisting of (a) water,

(b) a carboxylic acid having from l-8 carbon atoms;

and

(c) an anhydride of (b).

2. A process according to claim 1 wherein the bicyclic amidoacetal is of the formula not exhibit any attraction of ashes in this test (antistatic property, indicated by a sign). This antistatic behavior wherein is boiling-water-proof in case of polypropylene P (Ex- R is a member selected from the grou consisting of ample 18) and polyamide-IZ (Example 19) (see the hydrogen, an aliphatic residue of from 1-17 carbon table). atoms and aryl of 6 carbon atoms;

Ashes Film N-content test Blank value 0.025 Example 18 ..{O0ld water... }Po1ypropylene 0.72 Boiling water 0.52 Blank value- 6.86 Example 19 {Gold water... Polyamide-lZ 7.05 Boiling water- 7.05 amp e 0 gifig gg iij:::::} Y-( Y g yc terephthalate) EXAMPLE 21 each of R R and R is, independently, a member A film of polypropylene (Vestolen P) is immersed for seiectell iz the group conslstmg of an minutes at 100 C. in 5-methyl-4,6-dioxa-1-azabicyclo ahphatlc resl ue of 1 4 Carbon at 2; i [3,3,0]octane. Thereafter, as described in Examples 18- g $32 23 fi st 2122 2225231 2 g; 20, one sample is treated with cold water, and the second g y y y sample with boiling water.

The sample treated with cold water exhibits a nitrogen content of 0.48% and shows good antistatic behavior in the ashes test. The sample treated with boiling water likewise exhibits antistatic properties in the ashes test.

EXAMPLE 22 A film of polypropylene (Vestolen P) is treated, as set forth in Example 21, with 5-ethyl-3-phenyl-4,6-dioxal-azabicyclo[3,3,0]octane and subsequently with cold water and with boiling water. The sample treated with cold water (N-content 0.31%), as well as the sample treated with boiling water exhibit antistatic properties when subjected to the ashes test.

In like manner, each of the 4,6-dioxa-1-azabicyclo [3 ,3 ,0] octane and 5,7-dioxal-azabicyclo [4,3 ,0] nonanes encompassed herein can be used, either individually or in any combination, to improve dye receptivity and antistatic properties of synthetic hydrophobic thermoplastic polymers in the form of shaped bodies.

.'I'he used polypropylene (Vestolen P) exhibits a reduzierte Viskositat in a concentration of 0.1 g./ 100 ml. in xylol at 110 C. of 1 (red) =50.

The preceding examples can be repeated with similar success by substituting the generically or specifically described reactants and/or operating conditions of this invention for those used in the preceding examples.

From the foregoing description, one skilled in the art can easily ascertain the essential characteristics of this invention, and without departing from the spirit and scope thereof, can make various changes and modifications of the invention to adapt it to various usages and conditions. Consequently, such changes and modifications are properly, equitably, and intended to be, within the full range of equivalence of the following claims.

of 7 carbon atoms, alkenyloxymethyl of 4 carbon atoms; and

n is 2 or 3.

3. A process according to claim 2, wherein R is a member selected from the group consisting of hydrogen, alkyl having from 1-17 carbon atoms and phenyl;

each of R R and R is independently a member selected from the group consisting of hydrogen, lower alkyl, phenyl, and R may be alkoxymethyl of from 2-13 carbon atoms, lower alkenyloxymethyl and phenoxymethyl.

4. A process according to claim 2 wherein the bicyclic amidoacetal is 4,6-dioxa-1-azabicyclo[3,3,0]octane.

5. A process according to claim 2 wherein the bicyclic amidoacetal is 5,7-dioxa- 1-azabicyclo[4,3,0]nonane.

6. A process according to claim 2 wherein n is 2.

7. A process according to claim 2 wherein n is 3.

8. A process according to claim 2 wherein the polymer absorption of the amidoacetal is effected at a temperature of from 50150 C. and the ring cleavage is effected at 20l00 C.

9. A solid synthetic thermoplastic polymer composition wherein the polymer has absorbed therein a bicyclic amidoacetal selected from the group consisting of a 4,6-dioxal-azabicyclo[3,3,0]octane and a 5,7-dioxa-l-azabicyclo [4,3,0]nonane.

10. A composition according to claim 9 wherein the amidoacetal is a ring-cleaved bicyclic amidoacetal.

11. A composition according to claim 10 wherein from 0.0011% by weight, based on the polymer, is absorbed nitrogen from the amidoacetal.

12. A composition according to claim 10 wherein the polymer is a thermoplastic of a polyolefin, a vinyl polymer, a polyacrylate, a polyester or a polyamide.

13. A composition according to claim 10 wherein the bicyclic amidoacetal is 3,5-dimethyl-4,6-dioxa-l-azabicyclo [3,3,0]octane.

14. A composition according to claim 10 wherein the bicyclic amidoacetal is 5-methy1-4,6-dioxa-1-azabicyclo [3,3,0]octane.

15. A composition according to claim 10 wherein the bicyclic amidoacetal is S-ethyl-3-pheny1-4,6-dioxa-l-azabicyclo[3,3,0]octane.

16. A solid synthetic thermoplastic polymer composition having absorbed therein a ring-cleaved bicyclic amidoacetal of the formula wherein R is a member selected from the group consisting of hydrogen, alkyl having from 1-17 carbon atoms and phenyl;

each of R R and R is, independently, a member selected from the group consisting of hydrogen, lower alkyl, phenyl, and R may be alkoxymethyl of from 2-13 carbon atoms, lower alkenyloxymethyl and phenoxymethyl; and

m is either 1 or 2.

References Cited UNITED STATES PATENTS 2,676,896 4/1954 Cohen et a1 11762.1 3,106,482 10/1963 Van Dijlt et a1 117-62.1 3,288,631 11/1966 Jiirder 11762.1 3,236,685 2/1966 Caldwell et al 117-138.8 3,455,735 7/1969 Schwarz 117-138.8 3,098,692 7/1963 Cagliardi 117138.8

FOREIGN PATENTS 1,518,386 2/1968 France ll762.1

WILLIAM D. MARTIN, Primary Examiner M. SOFOCLEOUS, Assistant Examiner US. Cl. X.R.

8168, 172; l17-138.8E, 138.8F, 138.8N, 139.5CD; 260244R UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Pdtcnt No. 3,600,214 Dated August 17, 1971 Roland Feinauer, Wolfgang Seeliger, Johann Inventofls) Schlimme van Brunswiik. and Hans Busch It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In the Specification:

Col. 2, line 55, "1,2,33, 533" should be --l,233, 533--.

Col. 2, line 58, the first occurrence, change "in" to --is--,

Col, 4, line 61, "It" should be --If--.

Col. 5, line 69, the first occurrence, insert quote mark before "shaped".

C01. 8, line 10, "19" should be --10-- In the Claims:

Claim 1, line 11, "8" should be --l8--.

Signed and sealed this 9th day of January 1973.

(SEAL) Attest:

EDWARD M.FLET( IHER,JR. ROBERT GOTTSCHALK Attestlng Officer Commissioner of Patents FORM PO-WSO (10-69) USCOMM-OC 0017c PL) 

